Method of producing iron anodes



y 6, 1941. J. 1.. YOUNG 2,240,821

METHOD OF PRODUCING IRON ANODES Original Filed March 13, 1937 INVENTOR Patented May 6, 1941 METHOD OF PRODUCING IRON ANODES John L. Young, Pittsburgh, Pa., assignor, by mesne assignments, to Plastic Metals, Inc, a, corporation of New York Substituted for abandoned application Serial No.

130,715, March 13, 1937.

This application October 22, 1938, Serial N0. 236,589

2 Claims.

This invention relates to anodes for electrolytic cells; the object is an anode formed essentially of iron in metallic state, and of open or cellular structure. By virtue of its structure it presents large areas of surface to electrolytic action, and yet its integrity and massiveness are such as to afiord free flow of current to all its extent of surface. Invention is found in the method by which the anode is produced.

In the accompanying drawing Fig. I is a view in perspective of an anode of the invention; Fig. II is a view in perspective of a fragment of scrap material, such as has been found serviceable in the production of the anode of the invention;

and Fig. III is a view in perspective of the anode of the invention, produced from material such as thatindicated in Fig. II. The anode of Fig. III, when compared with that of Fig. I, presents an alternative embodiment of the product. As presently will appear, the method of production is essentially the same in thetwo cases.

In the practice of the invention a suitable quantity of iron in metallic state and in granular or finely divided condition-preferably granulated sponge iron-may be taken, and shaped and compressed by appropriate means to the formand dimensions desired. The body so shaped and compressed is brought, in a reducing atmosphere, to bright-annealing temperature. Under these conditions the relatively incoherent mass is converted into an integrated whole, of metallic homogeneity throughout, of porous or labyrinthine structure, and of high electrical conductivity throughout all its extent.

Inevitably it is true of any body of approximately pure iron that, exposed to the atmosph'ere, it acquires a surface coating of oxide; and

- inevitably it is true of the particles of a body of granular sponge iron exposed to the atmosphere, that the surfaces are coated with oxide. I have discovered. that, in' order to increase the effectiveness of a soluble iron anode in an electrolytic cell, not only'is it desirable to form the anode of finely divided metal, and so to increase the area of surface exposed to the electrolyte, but it is also highly advantageous to do what I have done,

namely, to unite the particles of metal by necks or bridges of iron in metallic state, homogeneous with and integral with the substance of the particles themselves, to the end that there shall be high conductivity and flow of electricity in freest measure throughout the body of the anode and to the surfaces over which the action of electrolysis progresses.

Informing an anode of granular sponge-iron,

' vided solely for my purposes.

therefore, my invention consists, not merely in giving coherence to the mass, but in reducing the oxide coating upon the grains and uniting grain to grain by bridges of iron'in metallic state, homogeneous with and-of integrity and continuity with the metallic bodies of the grains themselves. This, while maintaining without substantial diminution the essentially labyrinthine form of the body.

Ordinarily the practice will be to compress the mass, and in so doing to give to the mass" a density suflicient to make possible the ultimate integration, and acoherence sufficient for further handling; 'and then to subject the compressed mass to the action of a furnace of proper temperature whose atmosphere is 'of reducing nature. The furnace temperature will approximate 1000 C. and the furnace atmosphere will advantageously consist of or include hydrogen in state or condition to 'efiect reduction. In a word," the furnace will be a bright-annealing furnace. ployment as an anode, having labyrinthine structure, presenting large areas of surface to electrolytic action, and of high conductivity throughout its body.

Fig. I shows an anode l formed of sponge iron in the manner described. In Figs. II and III the use of'iron in another form, in the production of the anode of the invention, is illustrated. In this instance sheet-iron is used, and advantageously sheet-iron of relatively great attenuation. The degree of attenuation must in any case be 'sufilcient to permit of the crushing and anode-shaping operation. Beyond that, and

generally speaking, the thinner the sheet material, the more readily responsive it is to the practice of the invention. The sheet material 3 is, in Fig. II, indicated to be the scrap or waste remaining, after a plurality of otherwise useful discs has been cut from a continuous sheet. It will be manifest that in the practice of the invention scrap of this general sort may be employed, regardless of the shape, size and number of the articles cut from it; and it remains to add that the invention may be practised upon in tegral sheets, whether rejected from other operations because of defects, or prepared or pro- Such sheet material, of substantially pure iron, inevitably carries a surface coating of oxide.

In the practice of my invention the sheet material is crumpled, crushed and compressed to the form and dimensions of the intended anode, and the compression is so great 'as to bring multi- The product is a body capable of em-- tudinous small areas of sheet surface into intimate contact throughout the body. when theartiole has been so compressed it is subjected to such conditions of temperature and furnacev atmosphere as have already been described. The oxide coating is reduced, and bridges of metallic iron are formed over suchareas of surface con-' tact-bridges that are integral with and homo-- geneous with the substance of the sheet material.

The result is a labyrinthine article 4 (Fig, III), capable of presenting, when used as an anode,

large areas of surface for electrolytic action; and

an article of high electrical conductivity through- ;out, to the end that electrolysis may proceed at high rate.

In any case, such a body requires to be brought into continuity in the electrolytic circuit by means of a support or pole-piece that may be soluble (or iron, for example) or insoluble (of lead, for example). In any case the support or pole-piece will preferably be metallic; and care will advantageously be taken, in pursuance ofthe principle already considered, that, however extensive the areas of union, the meeting surfaces both'of the anode itself and of the support or pole-piece be at the time of or on the completion of the union bright and metallic, free of any conductivityimpairlng coating. In Fig. I such a currentestablishing member is exemplified in the polepiece 2, set in and engaging the substance of body I. To such a member the wire of an electrolytic 'circuit may be secured in known manner, as is pole-piece to' be of a metal from the state of oxide. and that the conductivity of the so completed article is superior;

Alternately the body of the anode may be shaped, lacking a pole-piece, and when so shaped may be subjected to bright-annealing conditions, and with the result described; and thereafter, and

preferably before the body has again been subiected to oxidizing conditions, the pole-piece may be cast in situ. A pole-piece of such insoluble metal as lead may thus be combined with the iron .anode, for lead in molten state wets iron.

This application is a substitute for my abandoned application Serial No. 130,715, filed March 13, 1937.

I claim as my invention.

1. The method herein described of making an iron anode of labyrinthine structure for an electrolytic cell'which consists in compressing to coherence but without loss of open, labyrinthine structure, a mass of discrete bodies of metallic iron having coatings of oxide, and subjecting the compressed article to a gaseous reducing atmosphere at a temperature'sufliciently high to reduce said oxide to the metallic state and thereby integrating adjacent bodies within the article.

2. The method herein described of making an iron anode of labyrinthine structure for an electrolytic cell which consists in compressing to coherence, but without loss of open structure, a mass of granulated sponge iron whose granules bear oxide coatings, and subjecting the compressed article to a gaseous reducing atmosphere at a temperature sufliciently high. to reduce said oxide to the metallic state and thereby integrating adjacent granules within the article.

JOHN L. YOUNG. 

